Uses

After you create a table in your database using the Liquibase createTable Change Type, you can populate it with data from an external CSV (comma-separated value) file using loadData. This may be useful when setting up a new application or migrating data from another system.

Syntax rules

• A value of NULL (regardless of capitalization) in a cell will be converted to a database NULL rather than the string NULL. Lines starting with a number sign (#) are treated as comments.

• You can change the comment pattern by using the commentLineStartsWith attribute. To disable comments, set commentLineStartsWith to an empty value.

If the data type for a load column is set to NUMERIC, numbers are parsed in the US locale (for example: 123.45). Date/Time values included in the CSV file should be in ISO format to be parsed correctly by Liquibase.

Liquibase initially sets the date format to yyyy-MM-dd'T'HH:mm:ss and then it checks for two special cases, which will override the data format string:

• If the string representing the date/time includes a period (.), then the date format is changed to yyyy-MM-dd'T'HH:mm:ss.SSS.

• If the string representing the date/time includes a space, then the date format is changed to yyyy-MM-dd HH:mm:ss.

Once the date format string is set, Liquibase will then call the SimpleDateFormat.parse() method attempting to parse the input string so that it can return a date/time. If problems occur, then a ParseException is thrown and the input string is treated as a String for the INSERT command to be generated. If UUID type is used, UUID value is stored as string and NULL in cell is supported.

Non-ISO date format

To use a non-ISO format for your dates:

1. Ensure you are using Liquibase 4.4.0 or later.

2. Add an ALTER SESSION command in SQL to your changeset.

3. Specify the DATE type in the affected columns of your loadData changeset.

For example, in an Oracle database using MM/DD/YYYY HH:MI:SS AM:

<changeSet author="Liquibase" id="0"> <sql> ALTER SESSION SET NLS_DATE_FORMAT = 'MM/DD/YYYY HH:MI:SS AM'; </sql> <loadData> <column name="EXPIRATION_DATE" type="DATE 'MM/DD/YYYY HH:MI:SS AM'"/> </loadData> <changeSet>

Load data with the loadData tag

Including specific columns

All CSV columns are used by default while generating SQL, even if they are not described in the columns property. If you want to skip specific headers in the CSV file, set the value of the type property to skip.

Imagine that you have a table with columns col_1,col_2,col_3. To load only columns col_1 and col_2, specify col_3 in the column tag and set its type to skip: <column name="col_3" header="col_3" type="skip" />

Creating a loadable CSV

You can load data from an existing CSV file (names.csv):

id,first,last 0,john,doe 1,eric,smith 2,cat,jones

In your changelog, create a table called populated. Then create a loadData changeset to insert data from the CSV into that table. For example:

<changeSet author="your.name" id="1::emptyTable"> <createTable tableName="populated"> <column name="id" type="int" autoIncrement="true"> <constraints primaryKey="true" nullable="false"/> </column> <column name="first" type="varchar(50)"/> <column name="last" type="varchar(50)"/> </createTable> </changeSet> <changeSet author="your.name" id="2::dataForTable" labels="data"> <loadData file="names.csv" tableName="populated"/> </changeSet>

In your command line, deploy your change: liquibase update

Note: Liquibase 4.4.0+ assumes that spaces in the CSV header are part of the column names and does not strip them. If your header contains spaces and the column names in your changeset don't, Liquibase throws an error. To resolve this, use the --trim-load-data-file-header parameter in Liquibase 4.29.0.

Generating loadData changesets and a CSV from your current database

You can also capture the current state of your database as a CSV with the generate-changelog command and dataOutputDirectory attribute. This generates the loadData changesets with the columns from the CSV, and formats your data as a CSV in the folder you specified for dataOutputDirectory:

liquibase generate-changelog --diffTypes=tables,columns,data --dataOutputDirectory=myData --changelog-file=output_changelog.xml

Example generated changelog (with dataOutputDirectory)

<?xml version="1.1" encoding="UTF-8" standalone="no"?> <databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext" xmlns:pro="http://www.liquibase.org/xml/ns/pro" xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd"> <changeSet author="adrian (generated)" id="1667231983827-1"> <loadData commentLineStartsWith="#" encoding="UTF-8" file="myData/populated.csv" quotchar=""" separator="," tableName="POPULATED"> <column header="ID" name="ID" type="NUMERIC"/> <column header="FIRST" name="FIRST" type="STRING"/> <column header="LAST" name="LAST" type="STRING"/> </loadData> </changeSet> </databaseChangeLog>

If you don't use the --dataOutputDirectory flag while running the command, Liquibase uses insert statements in your generated changelog instead of columns in the loadData tag, and also formats your data as a CSV in the folder you specified for dataOutputDirectory:

liquibase --diffTypes=tables,columns,data --changelog-file=myChangelog.xml generate-changelog

Example generated changelog (without dataOutputDirectory)

<?xml version="1.1" encoding="UTF-8" standalone="no"?> <databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext" xmlns:pro="http://www.liquibase.org/xml/ns/pro" xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd"> <changeSet author="adrian (generated)" id="1667315146413-1"> <insert tableName="POPULATED"> <column name="ID" valueNumeric="0"/> <column name="FIRST" value="john"/> <column name="LAST" value="doe"/> </insert> <insert tableName="POPULATED"> <column name="ID" valueNumeric="1"/> <column name="FIRST" value="eric"/> <column name="LAST" value="smith"/> </insert> <insert tableName="POPULATED"> <column name="ID" valueNumeric="2"/> <column name="FIRST" value="cat"/> <column name="LAST" value="jones"/> </insert> </changeSet> </databaseChangeLog>

Placeholder values

In Liquibase 4.31.0 and later, you can specify a null placeholder value in your loadData changeset. This allows Liquibase to translate corresponding values in your CSV into NULL values. This is an alternative to leaving a CSV cell blank, which Liquibase translates as an empty string.

For example, consider this changeset:

<changeSet id="nullPlaceHolderTest" author="your.name"> <loadData tableName="nullPlaceholderTable" file="nullPlaceHolderTestData.csv" relativeToChangelogFile="true"> <column name="test_col" type="COMPUTED" nullPlaceholder="testNullPlaceholder"/> <column name="other_col" type="varchar(100)"/> </loadData> </changeSet>

And this CSV file nullPlaceHolderTestData.csv:

colKey,col2 1+1,testNullPlaceholder 5,there

When you deploy this changeset, Liquibase searches for testNullPlaceholder in your CSV file and replaces any instances of that string with a NULL SQL reference.

Available attributes

Nested tags

Nested property attributes

Database support

Troubleshooting

CLOB data type handling

In Liquibase 4.29.2 and earlier, all CSV entries in a clob type column are assumed to be a path to a file. If Liquibase finds that file, it inserts the contents of the file into the table you're updating. If not, the execution stops with an error:

Caused by: java.io.FileNotFoundException: The file ExampleFileName was not found in the configured search path:

In Liquibase 4.30.0 and later, all CSV entries in a clob type column are assumed to be a path to a file by default. If Liquibase finds that file, it inserts the contents of the file into the table you're updating. If not, Liquibase inserts the string value as-is.